Mechanism for overcoming dead-centers



Patented Oct. Il,` |898.

ATTORNEYS,

W. H. JOHNSON.

Patented Oct. Il, |898.

MEGHANISM FOR VERCOMING DEAD CENTERS.

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(Application led Mar. 30, 1898.)

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No. 612,345. Patented Det. Il, |898. W. H. JOHNSON.

MECHANISM FOR OVERCOMING DEAD CENTERS.

(Application led Mar. 30, 1898.) (No Model.) 4 Sheets-Sheet 3.

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N0. 6|2,345. v Patented Oct. Il, |898. W. H. JOHNSON'.

MECHANISM FOR OVERCMING DEAD CENTERS.

(Application filed Mar. 30, 1898.) (No Model.) 4 Sheets-Sheet 4.

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NITED STATES PATENT OFFICE.

WILLIE H. JOHNSON, OF NAVASOTA, TEXAS.

MECHANISIVI FORv OVERCOMING DEAD-CENTERS.

SPECIFICATION forming part of Letters Patent N o. 612,345, dated October 11, 1898.

Application tiled March 30, 1898.

To au whom t may concern,.- p

Be it known that I, WILLIE HARRY JOHN- sON, of N avasota, in the county of Grimes and State of Texas, have invented a new and useful Improvement in Mechanism for Overcoming Dead-Centers, of which the following is a specification. v

My invention is in the nature of anI improvement upon the devices patented by me February 4, 1896, No. 554,223, for overcoming dead-centers; and it has for its object the simplification and cheapening of those devices, the reduction of friction and wear, and to provide also means for regulating the admission and discharge of steam to increase the efficiency of those devices.

It consists in the peculiar construction and arrangement of devices, which I will now proceed to describe with reference to the drawings, in which- Figure 1 is a side elevation with parts broken away to the line l l of Fig. 5. Fig. 2 is a similar View showing another position of the parts. Fig. 3 is still another view broken away to the same plane, but showing another position of the parts. Fig. 4 is a side elevation from the outside. Fig. 5 is a horizontal section on line 5 5 of Figs. l and 4. Fig. 6 is a detail of one of the locking-yokes. Fig. 7 is a detail of another locking-yoke, and Figs. Sand 9 are side views showing different positions of the valvegear.

In the drawings, A represents the base of the engine; A', the cylinder; A2A2,the guides;

A3, the piston-rod, and A4 the pitman or connectingrod. This connecting -rod has its wrist-pin connected to an arm B, which latter is pivoted at b tothe framework to rock about said point l) as a center. Within the arm B there is a longitudinal slot b', within which plays a pin c', having friction-roller,

which pin is fixed to an arm C. This arm C is pivoted at its lower end at c to the framework and at its upper end is provided with a longitudinal slot c2, that vreceives apind, with friction-roller, on the end of a rocking head D. This headD is fulcrumed upon trunnions or an independent axis d2, Figs. l and 5, and has a toothed segment-gear d', that engages with a corresponding toothed segment-gear e on a corresponding rocking head E. This latter rocking head is fulcrumed upon trunnions Serial No. 675,761. (No model.)

or an independent axis e2 and is connected at e to the crank F of the driven shaft S.

H H, Fig. 5, are side plates carrying the trunnions or axes d2 c2 of these heads D and F.. These side plates H H have trunnions H' H', rigid with the heads, arranged centrally and rocking in bearing-plates H2 H2, (see Figs. 4 and 5,) which slide within guides Gr G, friction-rollers R being arranged at the bearing-surfaces. Outside the sliding plates H2 each trunnion I-I has rigidly keyed to it a downwardly-projecting arm h, and beside it, rigidly bolted to the plate H2, is a downwardlyprojectingarm h. Fulcrumeduponthelower end of arm 7i is a locking-yoke h2, one end of which has an opening (see Fig. 6) that is adapted to lock over Ithe end of the rigid downwardly-projecting arm 71, from the action of a spiral spring h3, interposed between its opposite end and a foot or offset of the arm h, as seen in Fig. 4. A pin h4, with frictionroller, is carried on one end of the lockingyoke and is adapted to strike against the inclined stationary bar J and be deiiected down against the tension of spring h3 to throw the yoke h2 of the arm h'.

On the lower side of the segment-gear d (see Figs. 1 and 2) is formed an arm cl3, with elastic cushion d4, and on the lower side of segmental gear e is formed an arm c3, above which is pivoted or fulcrunied a locking-yoke e5, which has an opening in it (see Figs. 7, l, and 2) that is adapted to lock over the arm cl3 from the action of a spiral spring e4, arranged between the end of said yoke and an oifset or foot on the end of arm e3. Apin e6, with friction-roller, is arranged on the side and adapted in the horizontal reciprocation to strike an inclined and stationary arm J to throw the yoke e5 off the arm d3 against the tension of spring e4.

The operation of these parts is as follows: It will be borne in mind that the two segment-heads D and E and the sliding journal- IOO yII are left free to rock.

to the right it raises arm B about center b and through pin c also raises arm C. This, through pin d, lifts that end ot head D and rocking it about center d2 rotates the intermeshed segment-gears d e about their centers and throws the far end of head E, connectin g with crank F, in an upward direction, as shown by the arrows, and turns it off the dead-center. Then, following this action, as the piston nears the end of its stroke (see Fig. 2) the downward movement of arm B rocks the segment-heads D and E back again, as shown by the arrows, and then the heads D and E and plates H and H2 move longitudinally in their guides to the extreme right of-the stroke, as shown in Figs. 3 and 4. The action performed in the latter part of this stroke is to lock the two heads D and E on their centers and establish a new center of oscillation about the trunnions H H, in which action the two heads D and E instead of acting as two levers are made rigid and act as one lever about the new fulcrum-point of the trunnions H. This is for the purpose of giving the reverse action or downward thrust to the crank F necessary to carry it past the deadcenter when in the position shown in Fig. 4. This is eected as follows: First, to lock the 'heads D an'd E about their centers, (see Fig.

1,) as soon as the heads D and E move to the right far enough to carry the pin e6 away from the inclined bar J the spring e4 throws up the end e7 of the locking-yoke e5, and the latter encircles the arm d3, locking the heads together, as shown in Fig. 3. Then when the eXtreme limit of the stroke to the right is reached (see Fig. 4) the ypin h4 of locking-yoke h2 strikes the inclined bar J, and the lockingyoke h2 (which has heretofore locked together the arms h and 7L' and prevented the trun-V nions H of plates II from rocking) is now thrown off the rigid arm 7L', and the trunnions This they do as follows, referring still to Fig. 4: As the piston moves to the left arms B and C rise, and the connected end of head D also rises with them,

y:and the heads D and E being now rigidly locked and acting as one lever about trunnion-fu'lcrum II the crank end of E descends, as shown by the arrow, and the crank is carried past the dead-center. As the heads and plates pass to the left the yoke h2 passes off the inclined bar J, and the spring h3 causes the two arms 7i and h to be again rigidly locked as soon as they resume their position parallel to each other, and when the extreme limit of their stroke is reached (see Fig. l)

Ythe head-locking yoke e5 again passes under its inclined bar J', and the heads D and E are unlocked again for individual action about their centers to carry the crank F past the dead-center on its upward sweep again.

In my patent herein referred to I have employed the general principle ofv two centers of oscillation between the piston rod and crank alternating with one center of oscillation, and I do not claim this, broadly; but

with the toothed segments it will be seen that I not only simplify and lighten the weight of these moving parts, but l get a uniform motion between the segments, and by-making on the lower side of these toothed segments abutting faces :n and y, which come together, the segmentgears are stopped in proper position for the alinement of centers during the thrust upon and travel of these parts in the horizontal sliding movement. Corresponding abutting stop-faces and y are also formed on the arms h and h.

In adapting my device to work with the greatest efliciency I have devised a valvegear that is correlated to the dead-center mechanism. With my devices it is necessary in order to get the best results, for the reason that the engine is enabled to do work on the dead-center point, to provide means whereby 'steam is introduced exactly at the dead-center points as follows, referring to Figs. 8 and 9: The rod which operates the slide-valve is shown at m, a screw-threaded section m being arranged adjustably on the end of the same, so as to lengthen or shorten the rod, as may be required. This rod at its outer end is connected to a trunnionnut m2, arranged adj ustably upon the screwthreaded end of an oscillating lever n, ful-` crumed to an upright portion of the engineframe and having its lower end wrought into a toothed segmental head that engages a corresponding segmental head on a lever o, fulcrumed at o. The lever o has a rigid horizontally-projectin g tappet-arm r and a downwardly projecting arm o2, which latter is connected by a rodt to the lower end of a crank-arm r3 on a rock-shaft r2. This rockshaft at a point between the side walls of the mai-n frame is provided with a rigid tappetarm r, corresponding to the arm r. These arms r and'r are alternately thrown down and up to operate the slide-valvee-i'. e., when r is down r is up, and vice versa. The effeet of this is as follows: When r' is thrown up, shaft r2 is rocked, and the lower ends of crank 'r3 and lever o, with rod t, are thrown to the left of the position shown in Fig. S and the segment-gears between levers o and n throw the valve-rod to the left, all as shown by the arrows. When lever i' is thrown up and r down, the reverse action takes place. To do this exactly at the dead-center points, the tappet-arms fr and r are arranged immediately above the pins h4 and e6 of the lockingyokes h2 and e-that is, e is made to act upon and raise r and h4 is made to act upon and raise r. When one dead center is reached,- the locking-yoke e5 from its spring e4 iiies up, coupling the two heads together and simultaneously striking and lifting the tappet-arm r' and shifting the valve, and when the other dead-center is reached the other locking-yoke h2 outside the framework iiies up from its spring h3, coupling together the arms 71, and 7i. and simultaneously lifting the tappet-arm r and shifting the valve to the IIO opposite position. By this means the deadcenter mechanism will at the moment the dead-center is reached open the valve and cause steam to be admitted to the cylinder, thus doing elective work when the crank is on the dead-center.

To hold the valve to the position to which it is thrown by the instrumentalities described, a spiral spring w connects the trunnioned nut m2 to the lever 0 at or beyond its fulcrum o', so that when the valve is shifted the spring w passes from one side to the other of the fulcrum of lever n and holds the valve-gear to the limit of its throw.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a dead-center mechanism, the combination of two rocking heads having intermeshing segment-gears, reciprocating journal-plates for these heads, said journal-plates having an independent and intermediate fulcrum, and means for locking thegears to rock about their individual axes and means for locking the gears to rock about their common axis, substantially as shown and described.

2. In a dead-center mechanism, the combination of two rocking heads between the crosshead and the drivin g-crank having intermeshing segment-gears and abutting stop-faces,

toothed heads "substantially as 'and for the purpose described.

5. The combination of the rocking heads arranged on independent-axes and provided with intermeshing toothed segments; the locking devices for these heads, j ournal-plates H carrying the bearings of the heads and having intermediate trunnions or central shaft, bearing-plates H2 for the shaft, a rigid arm h' on said bearing-plates, an arm h rigidly fixed to the trunnion or central shaft, a locking-yoke h2 fulcrumed on arm h and having pin h4 and spring h3, and an inclined bar J for unlocking the yoke h2 substantially as and for the purpose described.

6. The combination with the crankshaft and the reciprocating rod in an engine; of a means interposed between the two for overcoming the dead-center, and a valve-gear operated upon by said means for admitting steam to the cylinder at the dead center points, substantially as and for the purpose described.

7. The combination with the crank-shaft, and the reciprocating rod in an engine; of an intermediate dead-center mechanism operating alternately about two centers as two levers, and then about one center as one lever, locking devices for alternately locking said mechanism about its single and double cenan oscillating support tor said heads and locking devices for the gears and said support substantially as shown and described.

3. The combination with the connectingrod and the crank-axle; of the rocking heads with intermeshing toothed segments d e', and subjacent arms d3 e3 abutting faces @c and y, the locking-yoke e5 pivoted to one of said arms and arranged to lock over the other, and means for operating it substantially as described.

ll. The combination with the connectingrod, and the crank-axle; of the support for the rocking heads and means for locking the same the rocking heads with intermeshing toothed segments d e and subjacent arms d3 e3, the locking-yoke e5 with pin e6 and spring e4, and the stationary inclined bar J adapted to operate upon the yoke e5 and unlock the ters, and a valve-gear operated by these locking devices substantially as and for the purpose described.

8. The combination with the dead-center mechanism; ofthe valve-rod, the toothed segment-levers n and o, the lever o having fixed thereto arm r adapted to be operated upon by the dead-center mechanism, a second arm fr also adapted to be operated upon by the deadcenter mechanism, a rock-shaft r2 rigidly attached to said arm 7" and having also arm rg, and a connecting-rod t connecting arm r3 and lever o substantially as and for the purpose described.

VILLIE H. JOHNSON.

Witnesses:

Enw. W. BYRN, SoLoN C. KEMON. 

